If he understood what was being said, he would hear: "You will be catalogued.

And "Category: unidentified."

And "You will be taken to a holding cell and catalogued."

Before he has a chance to get over the shock of his ankle, someone's got a needle in his neck (primary-type sedative, calculated for approximate body weight and presumed species, plus a little bit to be on the safe side) and then it doesn't matter what anybody's saying.